Substitution Effects on Olefin Epoxidation Catalyzed by Oxoiron(IV) Porphyrin p-Cation Radical Complexes: A DFT study
Substitution Effects on Olefin Epoxidation Catalyzed by Oxoiron(IV) Porphyrin p-Cation Radical Complexes: A DFT study
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Oxoiron(IV) 卟啉对阳离子自由基配合物催化烯烃环氧化的取代效应：DFT 研究
DOI：
10.1002/jcc.25831
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
and Masahiko Hada
中科院分区：
文献类型：
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作者：
Zhifeng Ma;Kasumi Ukaji;Naoki Nakatani;Hiroshi Fujii;and Masahiko Hada
采用密度泛函理论（DFT）方法，在四重态和六重态自旋多重性下，系统研究了外围氟原子对氧代铁卟啉阳离子自由基配合物环氧化乙烯反应的影响.使用乙烯和具有取代的氟原子的Fe（IV）OCl-卟啉的模型系统确定总体反应路线。通过获得过渡态和中间体化合物的能量图和电子和自旋密度差等值线图，我们证实，随着氟原子数量的增加，外围氟原子的吸电子增强了反应性，正如实验所观察到的那样。用内禀反应坐标方法讨论了四重态和六重态自旋多重数之间的系间交叉。我们得出结论，速率控制步骤位于第一过渡态（TS 1），用于激活C → C和Fe → O键，并且基态电子态在TS 1附近从四重态转变为六重态。© 2019 Wiley Periodicals，Inc.
The effects of peripheral fluorine atoms on epoxidation reactions of ethylene by oxoiron(IV) porphyrin cation radical complex in the quartet and sextet spin multiplicities are systematically investigated using the DFT method. The overall reaction routes are determined using a model system of ethylene and Fe(IV)OCl‐porphyrin with substituted fluorine atoms. By obtaining the energy diagrams and electron‐ and spin‐density difference contour maps of the transition states and intermediate compounds, we confirm that the electron‐withdrawing by peripheral fluorine atoms enhances the reactivity as the number of fluorine atoms increases, as is observed experimentally. The intersystem crossing between the quartet and sextet spin multiplicities is discussed by means of the intrinsic reaction coordinate method. We conclude that the rate‐determining step is located at the first transition state (TS1) for the activation of CC and FeO bonds, and the ground electronic state changes from quartet to sextet around the TS1. © 2019 Wiley Periodicals, Inc.